Propeller



J. H PILET May 10, 1932.

PROPELLER Filed Aug. 3, 1929 INVENTOR. Joy/vb. 1 0.57?

ATTORNEYS Patented May 10, 1932 UNITED STATES JOHN H. PILE'I, or SANFRANCISCO, c LIronNra PROPELLER Application filed August 3, 1923.1Serial 1w... 383,246. I

My invention relates to improvements in propellers, and it consists inthe combinations, constructions and arrangements hereinafter describedand claimed.

; An object of my invention is to provide a propeller that may consistof two or more blades, these blades having a greater pitch than theusual propeller, and the ends of the blades are turned inwardly withrespect to the blade lengths for presenting spoons adapted for grippingfluid as the propeller is revolved. I have found that this spoon type ofblade will hold the water to a greater extent and will prevent slippage.This results in a blade which will give greater power when turning at aless number of R. P. M. than a standard blade.

I have also found that a blade slightly concave, the concave portiongradually dimin- 0 ishing as the tip of the blade is reached,

will give'a greater propelling force than will a blade not so designed.

A further object of my invention is to provide a device of the typedescribed which is extremely simple in construction and which is durableand efficient for the purpose intended.

Other objects and advantages will appear as the specification proceeds,and the novel features of the device will be particularly pointed out inthe claims hereto attached.

My invention is illustrated in the accompanying drawings, in which:

Figure 1 is a side elevation of the device, Figure 2 is a view similarto Figure 1 except that the propeller has been rotated through ninetydegrees,

Figure 3 is a rear elevation, and Figures 4, 5 and 6 are sections alongthe lines 4-4, 5-5 and 66 of Figure 2.

In carrying out my invention, I provide a propeller having a hub portion1 that is provided with a bore 2 for receiving a drive shaft. I show thepropeller as being provided with two blades 3 and 4, each beingidentical with the other. A description of one will therefore sufficefor both. It is obvious that more than two blades may be used withoutdeparting from the spirit and scope of my invention.

:Figure' 2 shows the blade'3 as extending away from the axis 5 ofthepropeller at ap proximately an angle of forty-five degrees. The bladehas a concave face 6. The curva ture of the face varies from a positionnearest the hub to one near the tipof the blade, Figure 4,shows the face6 as being hollowed. out. The section shown in Figure 4 is taken nearthe hub -1 as shown by the sectionline 4-4 in Figure 2. The concavesurface is lesspronounced nearer the tip 7 oftheblade 3 as shownby thesection in Figure At the same time, the blade is considerablywidernearer the tip than it is at the points near the hub. This gradual.diminishing of 55 the concavity of the-surface6 makes, the bladespoon-shaped lt; is the spoon-shaping of the blade which gives it thegreater driving force. p p I r r Figure: 1 clearly shows how eachbladeis '7 shaped somewhat like aspoon. The blade follows the straight line 8shown in F igure 1 through substantially one-half of the blade length.From the point X on to the. end of the blade, I provide a slight curveindicated 7 at 9. This curve extends away from the line 8. This curve issimilar to the curve of the end of a spoon. f r

Ofcourse, the face of theblade opposite the face 6 is convex as shown inFigure '4 by 30 the numeral 10. Figures 2 and 3 show how. the tips 7 oftheblades3 and 4 haveslightly curved ends 11 and 12, the'curve 11merging into the curved edge 13 of the blade, while the curve 12 mergesinto the curved edge 14. The outer edge 13 is slightly curved as shownin Figure 2, while the edge 14 is more abrupt-' 1y curved. It will benoted from Figure 3 that the entire lengths of the blades are curved ina clockwise direction through a small angle when looking at the rear ofthe propeller;

From the foregoing description of the various parts of the device, theoperation thereof may be readily understood.

The direction of revolution of the propeller when viewed from the rearof the latter (see Figure 3) is counterclockwise.

During the operation of the propeller, the water is held against theconcave faces 6 1.

(see Figure 3) and is kept against the faces throughout the entirecontacting of the propeller with the water. The spoon shape of eachblade prevents a waste of power. The gradual inwardly turning of theblade tips gives the blade vthe shape of a spoon. The I greater curve inthe face of the blade near the hub and the gradual diminishing of thiscurve to the tip of'the blade provides a propeller that has a greaterforce. The pro peller has less vibration slippagedue to its particularconstruction. This results, of

course, in a less consumption of power which i is shown in the saving offuel. The propeller acts in much 'the sarne manner as a screw as itforcesits way through the water. The p pe l l Qkeepst -ae oat goingfor-v wara in a steady course and causes: the. boat toridethe waterbetter without drawing any moundof water at-the rear of the boat.

A lth ough I have shown and described; one

embodiment of my invention, it is to be. understood that the same issusceptible of various" changes, as may come within the scope of theinvention as claimed without departing from the spirit thereof.

I claim: r Q

1, A propeller having rearwardly eXtend-. ing blades fashioned withconcave leading 3 andconvex trailing faces in transverse section, thesecurved iaces becoming less pro nounced toward the tips 0f. the blades,and the end portions of; the blades turned in? wardly with respect'totheblade lengths: for; P sentin el s apt d er gr pping-fl as, the propelleris revolved.

2. Apropell'er, comprising a. hub, and, blades; extending rearwardlytherefrom, in diverging relationwith each other, thelead:

ing faces of the blades being fashioned con; a cave in transversesection and gradually] flattening toward the outer blade ends, andformed with inwardly turned tipswith re:

spect to thebladelengths, presenting spoons adapted for, grippingyfluidas thepropellerris revolved, 1 said, blades, when viewed ,frorn, the

rear of the propeller, being gradually curved the inner edge of thetips, turned through substantially one-eighthfof a circle V JOIDI H1PILETL.

